diff --git a/lib/mom/instruction/block_yield.rb b/lib/mom/instruction/block_yield.rb
index 656540ff..873ab552 100644
--- a/lib/mom/instruction/block_yield.rb
+++ b/lib/mom/instruction/block_yield.rb
@@ -15,16 +15,20 @@ module Mom
     end
 
     def to_risc(compiler)
-      block = compiler.use_reg( :Block )
-      return_label = Risc.label(self, "continue_#{object_id}")
-      save_return =  SlotLoad.new([:message,:next_message,:return_address],[return_label],self)
-      moves = save_return.to_risc(compiler)
-      moves << Risc.slot_to_reg( self , Risc.message_reg ,:arguments , block)
-      moves << Risc.slot_to_reg( self , block ,arg_index , block)
+      return_label = Risc.label("block_yield", "continue_#{object_id}")
+      index = arg_index
+      compiler.build("BlockYield") do
+        next_message! << message[:next_message]
+        return_address! << return_label
+        next_message[:return_address] << return_address
 
-      moves << Risc.slot_to_reg(self, Risc.message_reg , :next_message , Risc.message_reg)
-      moves << Risc::DynamicJump.new(self, block )
-      moves << return_label
+        block_reg! << message[:arguments]
+        block_reg << block_reg[index]
+
+        message << message[:next_message]
+        add_code Risc::DynamicJump.new("block_yield", block_reg )
+        add_code return_label
+      end
     end
   end
 
diff --git a/lib/risc/method_compiler.rb b/lib/risc/method_compiler.rb
index ca6be086..81bcc8f0 100644
--- a/lib/risc/method_compiler.rb
+++ b/lib/risc/method_compiler.rb
@@ -155,8 +155,8 @@ module Risc
     end
 
     # Build with builder (see there), adding the created instructions
-    def build(&block)
-      builder.build(&block)
+    def build(source , &block)
+      code_builder(source).build(&block)
     end
 
     # return a new code builder that uses this compiler
diff --git a/test/risc/interpreter/blocks/test_assign_outer.rb b/test/risc/interpreter/blocks/test_assign_outer.rb
index c30cc8ed..9c6614d2 100644
--- a/test/risc/interpreter/blocks/test_assign_outer.rb
+++ b/test/risc/interpreter/blocks/test_assign_outer.rb
@@ -1,7 +1,7 @@
 require_relative "../helper"
 
 module Risc
-  class BloclAssignOuter < MiniTest::Test
+  class BlockAssignOuter < MiniTest::Test
     include Ticker
 
     def setup
@@ -20,7 +20,7 @@ module Risc
             SlotToReg, OperatorInstruction, IsZero, SlotToReg, SlotToReg,
             LoadConstant, SlotToReg, SlotToReg, RegToSlot, RegToSlot, # 40
             RegToSlot, RegToSlot, Branch, SlotToReg, SlotToReg,
-            RegToSlot, LoadConstant, SlotToReg, RegToSlot, SlotToReg, # 50
+            RegToSlot, SlotToReg, LoadConstant, RegToSlot, SlotToReg, # 50
             SlotToReg, SlotToReg, DynamicJump, LoadConstant, SlotToReg,
             SlotToReg, SlotToReg, RegToSlot, LoadConstant, RegToSlot, # 60
             Branch, SlotToReg, SlotToReg, RegToSlot, LoadConstant,
diff --git a/test/risc/interpreter/blocks/test_block_return.rb b/test/risc/interpreter/blocks/test_block_return.rb
index c32a2a58..f0fcf80e 100644
--- a/test/risc/interpreter/blocks/test_block_return.rb
+++ b/test/risc/interpreter/blocks/test_block_return.rb
@@ -12,32 +12,32 @@ module Risc
     def test_chain
       #show_main_ticks # get output of what is
       check_main_chain [LoadConstant, SlotToReg, RegToSlot, LoadConstant, LoadConstant,
-             SlotToReg, SlotToReg, RegToSlot, RegToSlot, RegToSlot,
-             RegToSlot, SlotToReg, SlotToReg, Branch, RegToSlot,
-             SlotToReg, SlotToReg, SlotToReg, SlotToReg, RegToSlot,
-             LoadConstant, SlotToReg, RegToSlot, SlotToReg, FunctionCall,
-             LoadConstant, SlotToReg, OperatorInstruction, IsZero, SlotToReg,
-             SlotToReg, LoadConstant, SlotToReg, SlotToReg, RegToSlot,
-             RegToSlot, RegToSlot, RegToSlot, Branch, SlotToReg,
-             SlotToReg, RegToSlot, LoadConstant, SlotToReg, RegToSlot,
-             SlotToReg, SlotToReg, SlotToReg, DynamicJump, LoadConstant,
-             RegToSlot, Branch, SlotToReg, SlotToReg, RegToSlot,
-             LoadConstant, SlotToReg, RegToSlot, RegToSlot, SlotToReg,
-             SlotToReg, SlotToReg, Branch, FunctionReturn, SlotToReg,
-             SlotToReg, RegToSlot, Branch, SlotToReg, SlotToReg,
-             RegToSlot, Branch, SlotToReg, SlotToReg, RegToSlot,
-             LoadConstant, SlotToReg, RegToSlot, RegToSlot, SlotToReg,
-             SlotToReg, Branch, SlotToReg, FunctionReturn, SlotToReg,
-             SlotToReg, Branch, RegToSlot, SlotToReg, SlotToReg,
-             RegToSlot, Branch, SlotToReg, SlotToReg, RegToSlot,
-             LoadConstant, SlotToReg, RegToSlot, RegToSlot, SlotToReg,
-             Branch, SlotToReg, SlotToReg, FunctionReturn, Transfer,
-             SlotToReg, SlotToReg, Syscall, NilClass]
+            SlotToReg, SlotToReg, RegToSlot, RegToSlot, RegToSlot, # 10
+            RegToSlot, SlotToReg, SlotToReg, Branch, RegToSlot,
+            SlotToReg, SlotToReg, SlotToReg, SlotToReg, RegToSlot, # 20
+            LoadConstant, SlotToReg, RegToSlot, SlotToReg, FunctionCall,
+            LoadConstant, SlotToReg, OperatorInstruction, IsZero, SlotToReg, # 30
+            SlotToReg, LoadConstant, SlotToReg, SlotToReg, RegToSlot,
+            RegToSlot, RegToSlot, RegToSlot, Branch, SlotToReg, # 40
+            SlotToReg, RegToSlot, SlotToReg, LoadConstant, RegToSlot,
+            SlotToReg, SlotToReg, SlotToReg, DynamicJump, LoadConstant, # 50
+            RegToSlot, Branch, SlotToReg, SlotToReg, RegToSlot,
+            LoadConstant, SlotToReg, RegToSlot, RegToSlot, SlotToReg, # 60
+            SlotToReg, SlotToReg, Branch, FunctionReturn, SlotToReg,
+            SlotToReg, RegToSlot, Branch, SlotToReg, SlotToReg, # 70
+            RegToSlot, Branch, SlotToReg, SlotToReg, RegToSlot,
+            LoadConstant, SlotToReg, RegToSlot, RegToSlot, SlotToReg, # 80
+            SlotToReg, Branch, SlotToReg, FunctionReturn, SlotToReg,
+            SlotToReg, Branch, RegToSlot, SlotToReg, SlotToReg, # 90
+            RegToSlot, Branch, SlotToReg, SlotToReg, RegToSlot,
+            LoadConstant, SlotToReg, RegToSlot, RegToSlot, SlotToReg, # 100
+            Branch, SlotToReg, SlotToReg, FunctionReturn, Transfer,
+            SlotToReg, SlotToReg, Syscall, NilClass, ]
       assert_equal 15 , get_return
     end
 
     def test_load_return
-      load_ins = main_ticks(43)
+      load_ins = main_ticks(44)
       assert_equal LoadConstant ,  load_ins.class
       assert_equal Parfait::ReturnAddress , @interpreter.get_register(load_ins.register).class
     end